Dosing dispensers of various geometries are disclosed in prior art patents; examples of such dispensers are disclosed in the following U.S. Pat. Nos: 634,515 issued to Wade on Oct. 10, 1899; 650,161 issued to J., W. H., & E. R. Williams on May 22, 1900; 969,729 issued to Smith on Sept. 6, 1910; 1,175,032 issued to E. R. Williams on Mar. 14, 1916; 1,144,525 issued to Blake on Jun. 29, 1915; 2,812,119 issued to Bethune on Nov. 5, 1957; 2,839,743 issued to Newson on Jun. 24, 1958; 3,073, 488 issued to Kompter on Jan. 15, 1963; 3,105,245 issued to Finkbiner on Oct. 1, 1963; 3,181,731 issued to Ellis on May 4, 1965; 3,339,801 issued to Hronas on Sept. 5, 1967; 3,407,412 issued to Spear on Oct. 29, 1968; 3,417,410 issued to Tietema & Rodak on Dec. 24, 1968; 3,781,926 issued to Levey on Jan. 1, 1974; 3,895,739 issued to Buchtel on Jul. 22, 1975; 4,168,550 issued to Lindauer on Sept. 25, 1979; 4,171,546 issued to Dirksing on Oct. 23, 1979; 4,186,856 issued to Dirksing on Feb. 5, 1980; 4,216,027 issued to Wages on Aug. 5, 1980; 4,281,421 issued to Nyquist, Kitko & Stradling on Aug. 4, 1981; 4,305,162 issued to Cornelisse, Callicott & Brunsman on Dec. 15, 1981; 4,307,474 issued to Choy on Dec. 29, 1981; 4,357,718 issued to Corsette on Nov. 9, 1982; 4,370,763 issued to Dolan on Feb. 1, 1983; 4,375,109 issued to Jones on Mar. 1, 1983; 4,419,771 issued to Richards on Dec. 13, 1983; and 4,308,265 issued to Kitko on Jan. 5, 1982.
Passive dosing dispensers similar to those of the present invention are disclosed in commonly assigned U.S. Pat. No. 4,208,747 issued to Robert S. Dirksing on Jun. 24, 1980 and entitled PASSIVE DOSING DISPENSER EMPLOYING TRAPPED AIR BUBBLE TO PROVIDE AIR-LOCK, which is hereby incorporated herein by reference. The dispensers of Dirksing '747 provide a means for trapping an air bubble as the dispenser is filled with tank water. The bubble later repositions itself to form an air-lock capable of isolating the solid product and liquid product solution in the dispenser from surrounding toilet tank water during quiescent periods. Without such isolation, active ingredient continually migrates by diffusion from the dispenser into the surrounding toilet tank water.
Such a product dispensing system is well adapted to a consumer product which may be used to dispense active ingredients such as hypochlorite solution to condition toilet tank and bowl water. The absence of any moving parts in the dispenser makes it possible to produce such a dispenser very inexpensively, such as by thermoforming two thin plastic halves and sealing them together. Such a dispenser may be made so economically that it is well adapted for use as a disposable dispenser which may be discarded after the active ingredients sealed therein are depleted.